1. Field of the Invention:
The present invention relates generally to a rearview mirror assembly for motor vehicles, and more particularly to an anti-glare rearview mirror assembly for motor vehicles which has a housing swingable to move a prismatic mirror disposed in the housing selectively between day and night positions.
2. Description of the Relevant Art:
As disclosed in Japanese Utility Model Publication No. 58-26202, one conventional automotive anti-glare rearview mirror assembly comprises a bracket attached to an external support member, a housing swingably supported on the bracket, a prismatic mirror fitted in the inner peripheral edge of the housing, and an operating tab cooperating with the bracket in serving as a toggle-type operating unit. The operating tab projects out of a tab slot defined in a lower portion of the housing. By turning the operating tab, the housing is angularly moved with respect to the bracket. Parallel, spaced attachment walls are integrally mounted in the housing, and have support projections with recesses. Stub shafts projecting from the bracket and operating tab, respectively, have both ends engaging in the recesses of the support projections, thus supporting the housing on the bracket. The bracket has central projections projecting outwardly from lateral sides thereof and are inserted in holder openings defined in the attachment walls to keep the housing and the toggle-type operating unit (bracket/operating tab).
In order to allow the housing to swing, the holder openings defined in the attachment walls should be large in size, and, as a result, gaps or clearances are produced between the projections and the edges of the corresponding holder openings after the rearview mirror assembly has been assembled. Therefore, when the housing is moved or flexed under an external load in excess of a certain level, the housing and the toggle-type operating unit may possibly be released out of engagement with each other. The projections/holder openings which are provided to keep the housing and the toggle-type operating unit in reliabe engagement are positioned substantially intermediate between a position in which the stub shaft of the bracket engages the support projection of the attachment wall and a position in which the stub shaft of the operating tab engages the support projection of the attachment wall. Accordingly, the housing and the toggle-type operating unit cannot effectively be prevented from being released out of engagement. More specifically, when the housing is deformed or moved under shocks applied, the stub shafts may first be forced out of the recesses of the support projections, and then the projections may come out of the holder openings. When inserting the projections into the holder openings, considerable forces are required to be applied, resulting in an awkward assembling process.
Japanese Utility Model Publications Nos. 53-24753 and 53-24754 disclose anti-glare rearview mirror assemblies. In the disclosed rearview mirror assembly structures, a holder plate is secured to a housing in covering relation to the front surface of a toggle-type operating unit so that the housing and the toggle-type operating unit will not be forced out of engagement even when the housing is deformed under external loads. According to these conventional arrangements, however, the number of parts including the holder plate is increased, and as a result the sturcture of the rearview mirror assembly is complex and time-consuming to assemble.